From “Some Plants Duplicate Their DNA to Overcome Adversity” (ScienceDaily, Aug. 3, 2011), we learn:
Whatever does not kill a plant may actually make it stronger. After being partially eaten by grazing animals, for example, some plants grow bigger and faster and reproduce more successfully than they otherwise would. In a new study, researchers report that one secret to these plants’ post-traumatic triumph lies in their ability to duplicate their chromosomes — again and again — without undergoing cell division.
While this process, called “endoreduplication,” is not new to science, no previous study had looked at it in relation to the seemingly miraculous burst of growth and reproductive fitness that occurs in many plants after they have been grazed, said University of Illinois animal biology professor Ken Paige, who conducted the study with doctoral student Daniel Scholes.
Actually, the fact that pruning some plants makes them grow more vigorously has been well understood for millennia; what we didn’t know was what was happening inside when its growth surged. A really interesting finding here is that only one of the two cultivars of Arabadopsis (“leafy green lab rat”) thaliana – A Columbia – responded favourably. The other dweebed out.
Why does it work?
The added DNA content could allow the plants to increase production of proteins that are needed for growth and reproduction, Scholes said. More DNA also means larger cells.
“Because you have more DNA in the nucleus, you must have a greater nuclear volume, which causes your entire cell to get bigger,” Scholes said. Increases in the size of individual cells can ultimately lead to an increase in the size of the whole plant.
The researchers believe wild plants evolved this process because it confers greater reproductive fitness. Maybe. But consider: The lusher the endoreduplicants grow back, the more likely they are to attract another visit from ruminants. They could actually be running faster than the dweebs genetically, just to stay in place. By contrast, the dweeb (Landsberg erecta) will look unattractive, not be visited again by ruminants, and thus ripen its seeds in peace.
In that case, both methods work from the point of view of reproduction, and we should expect to see both in nature. The endoreduplicant benefits the ecology much more than the dweeb by raising the biomass and supporting a varied population of life forms. To do this it just needs to keep running in place.